PHARMACOKINETIC INTERACTION BETWEEN LANSOPRAZOLE AND THEOPHYLLINE

The pharmacokinetic interaction potential of the new proton-pump inhib itor lansoprazole and theophylline was assessed in a double-blind, two -period (13-day duration per period), multiple-dose crossover study in 14 healthy male volunteers. Lansoprazole 60 mg or placebo once daily was coadministered with anhydrous theophylline 200 mg four times daily . Plasma theophylline concentrations were quantitated via high-perform ance liquid chromatography. Lansoprazole did not appear to affect subs tantially the absorption profile or clearance of theophylline. Theophy lline area under the plasma concentration-versus-time curve over the 6 -h dosing interval decreased slightly (13%) but statistically signific antly during lansoprazole coadministration. As the magnitude of this e ffect was small, this interaction is likely to be clinically insignifi cant.